Dad goes through sundowning where I don't know what he is talking about. Mostly about traveling and having someone take us somewhere or a relative owning a hospital. I mean things come from everywhere.Wonder how you handle it when your loved one goes off the rails.
https://www.agingcare.com/articles/sundowners-syndrome-133187.htm
My mother had relief from her symptoms with Ativan.
Good luck to you.
He's talking, or reminiscing and not making a lot of sense? Is this the sundowning?
That is NOT what I would call going off the rails! You are so lucky if this is the worst it gets!
Just listen to him. Engage in conversation. Imagine you are having a conversation with a 3 year old child, and the child's train of thought is imaginative, incoherent, and doesn't make much sense. Just go along with it as best you can. Just listen.
If you sense your dad is bothered, that is, he is over-tired, over-stimulated, anxious because it is getting dark, (again, think of a 3 year old) there are ways to minimize his sundowning.
One is to keep a very simple and consistent routine daily. The same activities at the same time every day. This will be comforting to the dementia brain.
Try to limit distractions and over-stimulation. Such as: too much noise, too many people, talking to him and asking him questions which are really taxing his brain.
Keep his space pleasantly lit. Not too bright, Not too dark or dim.
If he is getting tired, encourage a nap during the day. Make sure he is comfortable, in bed or a recliner, has been fed, had something to drink, and has gone to the bathroom. Let him have some peace and quiet so he can nod off easily. That may help prevent him feeling over-tired in the early evening.
Finally, one change I made when my husband was sundowning, was to start closing all the drapes before it started to get dark outside. Then I turned on the lights in the house, including the hallway and adjacent rooms. The dark spaces in the distance can look confusing or scary to someone with dementia, as they try to figure out their surroundings. This helped the first time I tried it.
Other than that when dad says something off the wall just reply with "oh really, how interesting." Never try and argue or correct them as you'll lose every time.
Your dad is now in his own little world and I'm guessing is quite content there, so just let him be, and go along best you can with what he's saying.